Radiation Goggles- It's True! (sorta)

[Chuck Cooper <cooperc@teleport.com>]

This is such a simple concept, I don't see why you can't just get a good

$300 night vision scope and some zinc sulphide and try it. Calibration

would be a trick though.



====================

Source: http://www.globaltechnoscan.com/21stMar-27thMar01/goggles.htm



Radiation goggles



Wear these special goggles and see radioactivity with your own eyes. One

of the problems with radioactive contamination is that it is

invisible. Smoke blackens, oil stains, chemicals discolour, but you

can't actually see dangerous ionising radiation with the naked eye.



But now a British company is working on a system that shows up

radioactivity as a glow in the dark. With a pair of modified military

night-vision goggles, scientists monitoring radioactive contamination at

the scene of a possible spill would be able to spot smears of

alpha-emitting radionuclides such as plutonium.



The radiation goggles designed by British Instrument Consultants (BIC)

in Warrington, Cheshire, are based on an old technique. Early last

century, nuclear pioneer Ernest Rutherford saw the flashes of light

given off by zinc sulphide when it is struck by alpha particles. The

effect, known as scintillation, is commonly used in radiation monitors

which convert the flashes of light into electronic signals.



BIC wanted to find a way of boosting the weak flashes given off by low

levels of radioactivity until they're visible to the human eye. To do

this, the company took a pair of night-vision goggles and tuned them to

highlight light wavelengths emitted by scintillating zinc sulphide.



The result, according to BIC spokesman Mike Scott, is that you can see

alpha contamination as low as 30 becquerels per square centimetre

as an intense glow on the goggles' green monochrome screen. "The main

advantage is being able to measure contamination of unusually

shaped objects," he says. "With standard probes it's very difficult to

get into nooks and crannies."



The goggles, which have been tested at the University of Liverpool,

would also enable staff monitoring an area to keep well away from

contamination. One disadvantage, though, is that you have to spray zinc

sulphide onto the area under investigation. And you can only use

the goggles out of doors at night because daylight swamps the sensitive

electronics, though filters might make it possible to see the glow in

ambient light, Scott says.



Nevertheless, Scott says some of the major players in the nuclear

industry, including the UK Atomic Energy Authority (UKAEA) and

British Nuclear Fuels (BNFL) have already expressed an interest. The

goggles could be useful in identifying hot spots of plutonium

contamination at the nuclear plants being decommissioned at Dounreay in

Caithness and Sellafield in Cumbria, he argues.



Scott, a physicist who has specialised in radiation measurement, accepts

some people would prefer a device that could detect lower levels

of contamination and other forms of radioactivity. But he is confident

that he can improve his design to highlight contamination down to

10 becquerels per square centimetre. He is also planning to investigate

other materials such as plastics that are susceptible to scintillation

from beta, neutron and gamma radiation.



Peter Burgess from Britain's National Radiological Protection Board says

that while BIC's idea is a clever notion, he is worried that

spraying potentially contaminated areas with zinc sulphide might send

radioactive particles into the air and worsen the clean-up problem.

But the UKAEA believes the technology "sounds very interesting" and

could be useful. "But we need to reserve judgement until we have

seen it demonstrated," a spokesman says. BNFL takes a similar tack,

arguing that the goggles are the "spark of an idea" that needs more

work and testing before they would be willing to use them.



Author: Rob Edwards, Edinburgh



New Scientist issue 17th March 2001









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